Despite returning 19 of 22 starters from the team’s base offense and defense last season, and adding two more bonafide starters in Darrelle Revis and Brandon Browner, there is plenty of competition for the Patriots expected this summer.

While many of the team’s new players, including nine rookie draft picks, will be fighting for positions on the underbelly of the team’s final 53-man roster, there is a distinct possibility that several of the team’s starting positions will change hands. And of course, there’s certain roles like slot cornerback, flex tight end, long snapper, and even kick returner that are up in the air.

Here’s a look at what positions are more susceptible to competition and what important roles still need to be filled.

X wide receiver

—Chuck Burton / AP photo

While Julian Edelman has dutifully filled the role of both outside and inside wide receiver, there has been no definite lock on the team’s X receiver, or outside receiver, role, especially when the Patriots favor three wide receiver sets. Aaron Dobson certainly has his claim as last season’s top draft pick. The second-round pick is expected to make a second year jump. There’s also, of course, newly signed receiver Brandon LaFell (pictured), who tallied 49 receptions for 627 yards and five touchdowns last season for Carolina. Kenbrell Thompkins will play heavy into the completion, as will Josh Boyce, the Patriots’ other draft pick at wide receiver in 2013.

Z wide receiver

—Al Bello / Getty Images

How much do you trust Danny Amendola? The talented but often injured slot receiver came to the Patriots with high expectations in 2013. But after missing four games, dropping a couple of key passes, and generally disappointing Patriots nation, his place in the starting lineup is not nearly as secure as it once was. Julian Edelman, for one, can and has done his job dutifully. But there are others in the throes that are waiting for an opportunity, including seventh round draft pick Jeremy Gallon and possibly Josh Boyce.

Center

—Elise Amendola / AP photo

Ryan Wendell has been the team’s starting center for the past two seasons, playing almost 100 percent of the team’s offensive snaps. In those two seasons, he’s allowed the most sacks in the NFL at his position (12) and saw a dramatic downturn in his overall pass blocking ability in 2013. The Patriots re-signed him anyway for another two years, $8.5 million. That doesn’t mean the Patriots aren’t looking to upgrade. They drafted Bryan Stork out of Florida State, an All-American for the national champions his senior season and a sizable upgrade at center. Wendell likely won’t see any favor with a new offensive line coach on board.

Right guard

—Jim Rogash / Getty Images

In same sense that Ryan Wendell shall likely see no favor, neither will Dan Connolly, who had to fight off Marcus Cannon last offseason to remain the team’s starting right guard. The Patriots drafted Florida guard Jon Halapio, a talented player for the Gators who the team feels like was a steal in the sixth round. He could play huge into the team’s long-term planning.

Flex tight end

—Stephan Savoia / AP photo

This position has seemingly been up for grabs since Aaron Hernandez’s arrest last offseason. While Michael Hoomanawanui has filled the role in a limited basis, while also operating as the team’s primary tight end, he has not fulfilled the broader role of being a pass catching threat. Backup D.J. Williams has also sought to compete here. Rookie Asa Watson could possibly play in the fold here. And if the Patriots make a move in free agency, there could be more competition yet.

Running back

—Jamie Squire / Getty Images

Stevan Ridley’s fumbles the past two seasons have been well chronicled. So have Shane Vereen’s injury troubles. Between the two, and their upcoming free agency in 2015, the Patriots will have strong competition at running back on all three downs. Ridley, the primary back for the Patriots, can find himself pushed by anyone from Brandon Bolden (also a free agent in 2015) to rookie James White. White, who caught 39 passes his senior year at Wisconsin, could also fill in as the team’s third down back, Vereen’s role on the team. And rookie free agents Roy Finch and Stephen Houston are both expected to compete for a place on the roster, a direct threat to Bolden’s roster spot.

Defensive tackle

—Jonathan Wiggs/Globe Staff

The Patriots loaded up at defensive tackle last year after Vince Wilfork and then Tommy Kelly went down with season-ending injuries. The Patriots drafted the explosive (but injured) Dominique Easley in the first round of the draft, and he will conceivably push Kelly and Wilfork for snaps. Promising players like Sealver Siliga, Chris Jones, and Joe Vellano will have their work cut out for them to earn playing time if the veterans are deemed healthy and can stay that way.

Strong safety

—Jim Rogash / Getty Images

Duron Harmon (pictured) is currently penciled in as the team’s starting safety opposite of Devin McCourty, but nothing is set in stone. After cutting Steve Gregory in the offseason, the Patriots picked up Patrick Chung for his second tour in New England. He’ll certainly compete for snaps with Harmon, who played solid as a rookie last year. He had only five missed tackles in 433 defensive snaps, according to ProFootballFocus.com. Chung had 13 missed tackles in 815 defensive snaps for the Philadelphia Eagles last year. Rookie Jemea Thomas, picked up in the sixth round of the draft, will also play into the mix, as will cornerback Logan Ryan.

Slot cornerback

—Michael Dwyer / AP photo

Much ado has been made about the two new Patriots cornerbacks, Darrelle Revis and Brandon Browner, and how the duo has improved New England’s secondary by their mere presence. Not much has been made of which returning defensive back will work in partnership with them in the team’s sub packages, both nickel and dime, as the Patriots defend against an every pass-happy NFL. Alfonzo Dennard and Kyle Arrington will likely battle for snaps with second-year pro Logan Ryan in the competition as well.

Long snapper

—Lynne Sladky / AP photo

Veteran Danny Aiken, who re-signed this offseason on a 1-year, $725,000 deal with $55,000 guaranteed, will be competing to keep his job with former Harvard long snapper Tyler Ott, who signed as a rookie free agent. Bill Belichick is known to bring in competition for the special teams group. After a couple of gaffes by Aiken last season, it’s no surprise that he’ll have to fight for his job again.

Kick returner

—Matthew J. Lee/Globe Staff

You might as well pick a name out of hat here. The Patriots are once again looking for a kick returner, and it appears both veterans and undrafted rookies are in the running. There are a number of returning Patriots on the roster with kick return experience, including Devin McCourty, Josh Boyce (pictured), Matthew Slater, and Shane Vereen. And then there are rookies who could likely make their biggest impact on the team as a returner, including seventh round draft pick Jeremy Gallon, Roy Finch, and Wilson Van Hooser. It’s a wide open race that, in all likelihood, won’t be decided anytime soon.

Backup defensive end

—Michael Dwyer / AP photo

Chandler Jones and Rob Ninkovich combined for 2,537 snaps last season, effectively dominating the edges for the Patriots. There’s a growing feeling that both Jones and Ninkovich need more rest this season. That means more opportunities for backup defensive ends, including seventh round draft pick Zach Moore. Carryovers like Michael Buchanan, Jake Bequette, and veteran free agent pickup Will Smith will all play into the competition. There certainly will not be room for everyone.

Backup linebacker

—Michael Dwyer / AP photo

The Patriots appear to be going into the 2014 season with Jerod Mayo, Dont’a Hightower, and Jamie Collins as the team’s top three linebackers. Veteran James Anderson is a late addition, but can provide versatility for the Patriots, especially on passing downs. Backups Steve Beauharnais, Chris White, Ja’Gared Davis, and a host of rookies are all fighting for a role on this team behind that core group. Beauharnais, who was on the team’s 53-man roster much of last season but often did not dress for games, is likely at the forefront of this group. But nothing is guaranteed for him or anyone else for that matter.

Backup safety

—Jim Rogash / Getty Images

While Duron Harmon and Patrick Chung battle it out for the starting spot opposite of Devin McCourty in the secondary, who falls behind them will be just as important, particularly for sub packages. Third-year pro Tavon Wilson, utilized in the team’s dime packages in the past, never seems to have a role locked up with the Patriots. Nor does Nate Ebner. Rookies Jemea Thomas and Gary Shamiel will be looking to shake things up. Kanorris Davis is also in the mix.

Backup tight end

—Jim Rogash / Getty Images

Rob Gronkowski is the Patriots’ primary tight end. His place is secure on the team’s roster. But given his susceptibility to injury, his backup will be just as important this year. The Patriots didn’t make a move in the draft to address the issue, but did follow up by signing rookies Justin Jones (pictured) and Asa Watson, only one of whom fits the bill as a Y tight end. Jones, who stands a monstrous 6-8, is only matched in height by Patriots Nate Solder and Sebastian Vollmer as the tallest on the team. He certainly can be a primary blocking tight end. Michael Hoomanawanui has also filled this role. The veteran was just re-signed on a 2-year, $2.4 million deal.